Curency converter 1- Java

import java.util.Scanner;

/**
 * Created by AiKiHack on 11.03.17.
 */
public class p12_CurrencyConverter {
    public static void main(String[] args) {
        Scanner consolein = new Scanner(System.in);
        double rateBGN = 1.0;
        double rateUSD = 1.79549;
        double rateEUR = 1.95583;
        double rateGBP = 2.53405;
        double inputSum = Double.parseDouble(consolein.nextLine());
        String currIn = consolein.nextLine();
        String currOut = consolein.nextLine();
        double result;
        switch (currIn){
            case "BGN": switch (currOut){
                            case "USD": result = inputSum/rateUSD; break;
                            case "EUR": result = inputSum/rateEUR; break;
                            case "GBP": result = inputSum/rateGBP; break;
                            case "BGN": result = inputSum; break;
                            default: result = 0; currOut = "ERROR"; break;
            } break;
            case "USD": switch (currOut){
                            case "BGN": result = inputSum*rateUSD; break;
                            case "EUR": result = inputSum*rateUSD/rateEUR; break;
                            case "GBP": result = inputSum*rateUSD/rateGBP; break;
                            case "USD": result = inputSum; break;
                            default: result = 0; currOut = "ERROR"; break;
            }  break;
            case "EUR":switch (currOut){
                           case "USD": result = inputSum*rateEUR/rateUSD; break;
                           case "BGN": result = inputSum*rateEUR; break;
                           case "GBP": result = inputSum*rateEUR/rateGBP; break;
                           case "EUR": result = inputSum; break;
                           default: result = 0; currOut = "ERROR"; break;
            }  break;
            case "GBP": switch (currOut){
                            case "USD": result = inputSum*rateGBP/rateUSD; break;
                            case "EUR": result = inputSum*rateGBP/rateEUR; break;
                            case "BGN": result = inputSum*rateGBP; break;
                            case "GBP": result = inputSum; break;
                            default: result = 0; currOut = "ERROR"; break;
            } break;
            default: result = 0; currOut = "ERROR"; break;
        }

        if (!currOut.equals("ERROR")) {
            System.out.printf("%.2f %s", result, currOut);
        }
    }
}